1. Field of the Invention
The present invention relates to a method for producing a phenol condensate.
2. Description of the Related Art
A phenol condensate is a dehydrogenated condensate which is produced formally by removing hydrogen atom from phenol compound and the dehydrogenated species are connected with one another. As a method for producing thereof, it has been known that a phenol compound is subjected to oxidative condensation in the presence of catalyst and oxygen.
For example, it is known that, when 2,6-disubstituted phenol compound is subjected to oxidative condensation in the presence of copper complex and oxygen, poly(2,6-disubstituted-1,4-phenyleneoxide) is obtained by coupling of a para-positioned carbon atom with oxygen atom.
On the other hand, when a phenol condensate is produced by subjecting a phenol compound not having a substituted group on at least one ortho-position to oxidative condensation, there has been a problem that condensates coupled not only at the para-positioned carbon but also at the ortho-positioned carbon are formed.
The present inventors have reported a method for producing phenol condensate (Macromolecules 33, 1986 (2000)) that 4-phenoxyphenol, which is a phenol compound not having a substituted group on at least one ortho-position, is subjected to oxidative condensation in the presence of a copper complex represented by the following formula and of oxygen,
wherein R is n-butyl group, isopropyl group or cyclohexyl group; however the yield of condensate coupled at the para-position is not yet sufficient.